1. Field of the Invention
The invention relates to a needle thread wiper for a sewing machine for retaining the needle thread connected to the needle, which is stopped at the top stopping position, and is cut off from the cloth, so as not to slip off from the tip of the needle.
2. Description of the Prior Art
This type of needle thread wiper for a sewing machine is disclosed, for example, in Japanese Utility Model Publication No. 61-8863. What is disclosed herein comprises, as shown in FIG. 4 herein, a guide 103 having a U-section with its upper end fixed to the side of the arm head of sewing machine 101, and a thread capturing element 104 slidable along the groove 103a of the guide 103. In the portion excluding the lower part of the guide 103, a cover 105 for covering the opening of the groove 103a is provided. The guide 103 is bent approximately in a J-form so that its lower end may approach the needle thread connected to the needle thread passage between the needle 102 stopped at the top position and the cloth (not shown). The bottom surface of the groove 103a forms the guide surface of the thread capturing element 104 communicating with the upper and lower ends of the guide 103. On the other hand, the thread capturing element 104 is formed as a plate extending along the guide surface of the guide groove 103a, and at its front end there is a hook 104a for capturing the needle thread. Meanwhile, the thread capturing element 104 is flexible so as to press the hook 104a to the guide surface of the groove 103a at the bent part of the guide 103. This thread capturing element 104 is engaged with the groove 103a slidably between the action position of crossing the needle thread passage and the waiting position of having the hook 104a pressed to the bottom of the groove 103a. That is, when the hook 104 a at the waiting position is projected along the groove 103a, this hook 104a moves across the needle thread passage. The thread capturing element 104 is usually held at the waiting position by action means not shown herein, and is also allowed to move to the action position after the needle stops at the top position.
In such a conventional needle thread wiper for a sewing machine, however, the needle thread captured and pulled by the hook 104a is held between the guide groove 103a and hook 104a. Accordingly, if this holding force is strong, the needle may be broken by the tensioning on the thread when next starting the sewing machine. In particular, in multineedle double chain stitch sewing machines or the like for capturing and pulling plural needles by one hook, this holding force was very strong, and the risk of needle breakage was hence very high.